Crop residue produced by a modern combine is typically generated by two sources, and is of two consistencies. One source is the threshing and separating system, which produces a large volume of crop residue that has a larger, heavier consistency, typically including fragments of stalks, stems, cobs, and leaves. The other source is the cleaning system, which produces a much lower volume of much smaller, lighter elements, such as pod and husk fragments, and particulates, commonly referred to as chaff. The larger, heavier crop residue is typically easier to spread over a wide swath, due to its mass, whereas the chaff is more difficult, due to its lower mass. Wind will also present a difficulty to spreading chaff evenly.
Recent trends have been toward larger combines having wider headers capable of harvesting swaths of forty feet and wider. Another recent trend is to attempt to spread the crop residue as evenly as possible over the width of a swath, with less clumping, to provide benefits such as more even breakdown and decomposition of the residue for improving soil composition, improved soil coverage and erosion prevention for conservation, and more uniform soil temperature, moisture distribution, and other conditions for germination and emergence of the next crop. This latter trend presents a challenge, primarily due to the above-mentioned difficulty of spreading smaller and lighter chaff over wider swaths.
One approach that has been generally successful for achieving wider chaff spreading, has been to spread the chaff mixed with the larger residue. This has been found to be successful in some instances, as the larger crop residue essentially helps to carry the lighter chaff. Reference in this regard, Schmidt et al., U.S. Pat. No. 6,893,340 entitled Rotary Accelerating Apparatus for a Vertical Straw and Chaff Spreader of an Agricultural Combine, which has been found to provide a satisfactory combined straw and chaff spreading capability over a wide swath. However, for many applications, particularly when harvesting small grains such as wheat and legumes such as soybeans, it is additionally desired to provide a capability for chopping the larger crop residue prior to spreading.
Integrating a chopping capability with mixed straw and chaff spreading, can be problematic for several reasons, particularly with regard to material flow. Many known combines are equipped to convey or propel the crop residue from the threshing and separating system rearwardly through a rear cavity of the combine to a rear end thereof. At the rear end, the crop residue will be either discharged directly onto the field, for instance, in a windrow (mainly straw), or directed into a chopper, which will chop and distribute the residue on the field. A separate spreader can also be provided for spreading the chopped residue. Reference in this regard Roberg, U.S. Pat. No. 5,833,533, entitled Harvester Thresher.
In a combine, the chaff is typically discharged from the cleaning system at a more forward location, relative to the chopped residue from the threshing and separating system, and to mix the chaff with the crop residue from the separating system, the flow of chaff and the flow of chopped residue must be brought together. Reference in this regard, Guinn et al., U.S. Pat. No. 4,637,406, entitled Chaff and Straw Spreading Attachment for Combines, which illustrates use of a fan for blowing a stream of chaff into a chopper for mixing with the chopped residue from the separating system. Reference also, Holmen, U.S. Pat. No. 6,881,145, entitled Harvester Combine, which uses a large inclined pan for conveying the chaff rearwardly to a spreader operable for propelling and mixing the chaff into a chopped residue flow from a chopper. However, both of these disclosures require some additional apparatus, e.g., a fan or pan, for carrying the chaff rearwardly. Additionally in the latter disclosure, the mixed flow is primarily directed rearwardly from the combine, and it can be difficult to provide uniform crop residue coverage over a wide swath e.g., 40 or more feet, using a rearwardly directed discharge pattern, as opposed to a sidewardly directed pattern.
Thus, what is sought is apparatus that overcomes at least one of the problems, shortcomings and disadvantages set forth above.